The only problem with mines is their explosion... Have you ever noticed this effect is tiny ?

Well, depends on what you mean 'tiny'. On unit clutters for chokepoint levels, rushes from enemy groups explode. Against vehicles, alone it would be tiny, but with 4, the standard scout/medium assault vehicle, would be at around %10hp. The downfall is, even if you have team damage off, your team-mates will most likely get caught in the action of the mines, and you'll lose a couple of kills. I love mines, but I hate my AI units.